Densely deployed heterogeneous networks (HetNets) are destined to become the future of commercial wireless communications systems. A motivation is to deal with a scarcity of resources among increasing demand for data services. Densely deployed small cells are expected to improve the spectral efficiency of the wireless communications system and provide data rate enhancement for high speed data service. However, as the wireless communications systems become denser, inter cell interference (ICI) becomes a major source of performance degradation.